During compressor shutdown, refrigerant accumulation and absorption takes place in the oil sump or crankcase and thereby dilutes the lubrication oil resulting in a refrigerant and oil mixture. The refrigerant condenses and accumulates in the compressor because it tends to be one of the lowest temperature points in the system, due to the thermal gradient in the system and because of the affinity of halocarbon refrigerants for oil. Under normal operating conditions, some oil circulates with the refrigerant and will be returned to the compressor oil sump during continuous operation. In the case of a low side compressor, the casing will generally have an equilibrium pressure, after shutdown, which is greater than the suction pressure during operation. With the oil sump being directly connected to the suction plenum, their equilibrium pressures are identical. This will cause liquid refrigerant to migrate to the oil sump and a flooded start condition will exist because of the refrigerant in the sump. Specifically, at start up, the suction plenum and thus the pressure of the gaseous refrigerant over the oil sump, will be drawn down towards suction pressure. However, as the pressure in the suction plenum and oil sump is reduced, the liquid refrigerant in the oil starts boiling off creating a froth or foam. Froth will be generated as long as the pressure is being reduced in the oil sump and refrigerant is dissolved in the oil. As a result, the oil pump draws in froth rather than liquid oil and delivers gaseous refrigerant to the lubrication system. Pumping gas prevents the system from developing oil pressure and the gaseous refrigerant interferes with the lubrication process.